Pyramid Lake is the terminus of the Truckee River, which flows from Lake Tahoe, about 70 miles and a couple thousand feet away. It was at the level of the white line on the pyramid to the right until the first Bureau of Reclamation project opened about 100 years ago, which diverted water from the Truckee to the Carson sink. The diversion also completely dried up another lake to the east, which was far more shallow and seasonal, but a great wildlife area. Now it’s dust, but hey, cantaloupes from Fallon! A similar lake to the south, Walker Lake, has been even more severely drained, dropping 120ft in the last 100 years, which is endangering one of the habitats of the Lahontan Cutthroat Trout, a fish that takes its name from the massive lake that used to include what are now Walker and Pyramid Lakes.
Pyramid was named by Fremont as he passed through, for obvious reasons. It’s currently the Pyramid Lake Paiute Reservation.